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Education Why are batteries refered to as flat?

Discussion in 'General' started by steveo_mcg, 19 Apr 2010.

  1. steveo_mcg

    steveo_mcg What's a Dremel?

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    As title, why when a batter reaches the end of its life do we call it flat? Had a look on google but can't see anything, so with the huge pool of knowledge round here, what you got?
     
  2. smoothie

    smoothie What's a Dremel?

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    I've never heard that term before (I'm in the US). We call them "dead" batteries.
     
  3. xrain

    xrain Minimodder

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    Because they become like a flat soft drink? no zip left in them...
     
  4. M7ck

    M7ck Ⓜod Ⓜaster

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    This is just a guess but I think its because if you test a battery that has no power then the multimeter will just stay "flat".
     
  5. specofdust

    specofdust Banned

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    Just a lowly educated guess, but I'd assume because on an oscilloscope electricity makes spikes and curves, but when a battery is out of juice the line will be flat.
     
  6. Journeyer

    Journeyer Minimodder

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    +1
     
  7. Moriquendi

    Moriquendi Bit Tech Biker

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    The line will be flat even for a charged battery, only a changing voltage will produce spikes and waves on an oscilloscope.

    Moriquendi
     
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  8. CardJoe

    CardJoe Freelance Journalist

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    Because you've run them flat. Can't get a blip out of them.
     
  9. Prime

    Prime What's a Dremel?

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    +1 to Moriquendi.

    The term probably originates from the heaviside function which is used to model current or from the early electro-chemical cells which would probably have gone dry or stopped fizzing (producing hydrogen) and hence gone flat
     
  10. xrain

    xrain Minimodder

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    Even if you put a dead battery on a multi-meter, It will still output a voltage. For example, a charged 12 volt car battery will read around 12.5-13.5 volts on average, and <11 when dead.

    And Moriquendi is right on the flat line on the oscilloscope part, although its possible the voltage might also fluctuate when discharging battery also. But the only kind of power source that will give a non flat reading on an oscilloscope would be AC power, since it alternates between negative voltage and positive voltage. And since no batteries store power in AC the point is moot.

    I still think it has to do more with the connotations the word flat has, because you can have a flat tire, or a flat can of beer, or live in Flat, Alaska... None of which are good, but the most common way to refer to a uncharged battery would to call it dead.
     
  11. steveo_mcg

    steveo_mcg What's a Dremel?

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    Wheres John when you need him, he can perhaps explain why he coined the term.

    I'd say in the UK flat is more common than dead though.
     
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  12. knuck

    knuck Hate your face

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    Maybe it's just slang. Just like here. We say "la battery est à terre", which literally means "the battery is on the ground"

    French (real ones) find it really funny when we say that... Meh
     
  13. Moyo2k

    Moyo2k AMD Fanboy

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    Batteries don't really truly die, not for a very long time anyway, they just drop out of a useful voltage range, which is why you can take the 'flat' batteries out of a high power device, like maybe an Xbox controller and it will still work in a lower demand device like maybe a TV remote, Alkaline batteries start at 1.5 (usually actually like 1.6V) and the lowest I've ever measured was about 0.5V on an alkaline battery that had been in storage for ages

    An Moriquendi is right, an oscilloscope will only show a waveform for AC, Sawtooth etc.. voltage types, DC is a flat line all the time
     
  14. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    Never say never always - DC ripple can be a serious problem!
     
  15. Moriquendi

    Moriquendi Bit Tech Biker

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    It's called DC ripple but in actually it should be described as an AC waveform superimposed on the DC voltage, DC is DC and will always give a flat line, if it doesn't then it's not strictly DC.

    Moriquendi
     
  16. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    Very true, but it sucks when it shows up in your DC waveform while you're still set to DC coupling. Time to bust out some smoothing caps, anyway.
     
  17. boiled_elephant

    boiled_elephant Merom Celeron 4 lyfe

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    That's a hell of a tautology there, you basically said "we call them that because we call them that"!

    I call them flat because **** YOU ESPERANTO, I LIKE MY LANGUAGE ARBITRARILY ILLOGICAL
     
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  18. Lorquis

    Lorquis lorquisSpamCount++;

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    They're called flat, because yo' momma sat on them.

    Done.
     
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  19. Ending Credits

    Ending Credits Bunned

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    We call them flat because they are not not flat anymore. :thumb:
     
  20. Moriquendi

    Moriquendi Bit Tech Biker

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    Yup, I think that the way a 'scope works is that with AC coupling there's a cap or a transformer in series that blocks any DC component while DC coupling goes straight through so it'll show any AC component as well.

    Moriqendi
     

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